US20080274623A1 - Methods for fabricating a magnetic head reader using a chemical mechanical polishing (cmp) process for sensor stripe height patterning - Google Patents
Methods for fabricating a magnetic head reader using a chemical mechanical polishing (cmp) process for sensor stripe height patterning Download PDFInfo
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- US20080274623A1 US20080274623A1 US11/743,404 US74340407A US2008274623A1 US 20080274623 A1 US20080274623 A1 US 20080274623A1 US 74340407 A US74340407 A US 74340407A US 2008274623 A1 US2008274623 A1 US 2008274623A1
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- 238000005498 polishing Methods 0.000 title claims abstract description 8
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- 238000000059 patterning Methods 0.000 title abstract description 8
- 239000010410 layer Substances 0.000 claims abstract description 126
- 239000011241 protective layer Substances 0.000 claims abstract description 85
- 239000012212 insulator Substances 0.000 claims abstract description 52
- 238000000151 deposition Methods 0.000 claims abstract description 29
- 230000000873 masking effect Effects 0.000 claims abstract description 24
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
- G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
- G11B5/3169—Working or finishing the interfacing surface of heads, e.g. lapping of heads
Definitions
- the invention is related to the field of magnetic recording head fabrication, and in particular, to improved methods of fabricating a read sensor which involve using a chemical mechanical polishing (CMP) process with a patterned conductive CMP protective layer for sensor stripe height patterning.
- CMP chemical mechanical polishing
- Magnetic disk drive systems typically include a magnetic disk, a magnetic recording head having read and write elements, a suspension arm, and an actuator arm.
- a magnetic disk As the magnetic disk is rotated, air adjacent to the disk surface moves with the disk. This allows the magnetic recording head (also referred to as a slider) to fly on an extremely thin cushion of air, generally referred to as an air bearing.
- the actuator arm swings the suspension arm to place the magnetic recording head over selected circular tracks on the rotating magnetic disk where signal fields are written to and read by the write and read elements, respectively.
- the write and read elements are connected to processing circuitry that operates according to a computer program to implement write and read functions.
- the magnetic recording head is typically produced using thin-film deposition and patterning techniques.
- the magnetic head reader fabrication involves two separate patterning processes. One process defines the stripe height of the read sensor, while another process defines the track width of the read sensor.
- the several material layers which make up a read sensor for a magnetic reader are typically formed by depositing full film sensor layers of the required materials on a wafer substrate, depositing and patterning a masking layer over the sensor layers to form a mask structure, etching the exposed portion of the sensor layers around the mask structure, and then removing the mask structure.
- CMP protective layers also called CMP stop layers
- CMP stop layers are deposited between various layers of the fabricated structure to protect other layers, such as sensor layers and insulation during the CMP lift-off process.
- These protective layers are then removed using another etching process (e.g., reactive ion etching or ion milling).
- the invention solves the above and other related problems with improved methods for fabricating a magnetic reader using a CMP process with a patterned CMP conductive protective layer for sensor stripe height patterning.
- the CMP process is used to planarize the insulator layer.
- the CMP process stops at the CMP conductive protective layer.
- the CMP conductive protective layer may be left in place as sensor cap of a read sensor of the magnetic reader.
- the invention eliminates the alumina bumps typically encountered by prior art stripe height definition processes using DLC protective layers.
- the invention also allows for the elimination of a second protective layer (e.g., a DLC layer) used in prior art stripe height definition processes.
- a first exemplary embodiment comprises a method for fabricating magnetic readers.
- the method comprises defining a read sensor of a magnetic reader.
- the method further comprises depositing an insulator layer on the read sensor.
- the method further comprises performing a CMP process down to a conductive protective layer deposited while defining the read sensor to remove an overfill portion of the insulator layer above the conductive protective layer and to remove a sensor pattern mask structure above the conductive protective layer.
- a second exemplary embodiment of the invention comprises a method for fabricating magnetic readers.
- the method comprises defining a stripe height of a read sensor of a magnetic reader.
- the read sensor has a field on side regions of the read sensor.
- a conductive protective layer is formed above a top portion of the read sensor to protect the read sensor.
- the method further comprises depositing an insulator layer on the read sensor.
- the insulator layer is deposited in the field of the read sensor to a height above the conductive protective layer.
- the method further comprises performing a CMP process down to the conductive protective layer.
- the CMP process removes an overfill portion of the insulator layer above the conductive protective layer, planarizes the insulator layer with the conductive protective layer and removes a sensor pattern mask structure above the conductive protective layer.
- the method further comprises defining a track width of the read sensor.
- the method further comprises depositing a bi-layer photo resistive structure on the magnetic reader.
- the method further comprises milling the magnetic reader to remove material on side regions of the bi-layer photo resistive structure.
- the method further comprises depositing insulator material on side regions of the bi-layer photo resistive structure.
- the method further comprises performing a lift-off process to remove the bi-layer photo resistive structure.
- the insulator layer is planarized and flush with the read sensor, eliminating fencing typically encountered at the edges of the insulator layer.
- a third exemplary embodiment is a method for fabricating magnetic readers.
- the method comprises depositing sensor layers.
- the method further comprises depositing a conductive protective layer on the sensor layers.
- the method further comprises depositing a masking layer on the conductive protective layer.
- the masking layer is etchable for definition of a mask structure.
- the method further comprises etching the conductive protective layer around the mask structure to remove a portion of the conductive protective layer.
- the method further comprises etching the sensor layers to define a stripe height of a read sensor of the magnetic reader.
- the method further comprises depositing an insulator layer on the read sensor.
- the method further comprises performing a CMP process down to the conductive protective layer.
- the invention may include other exemplary embodiments described below.
- FIG. 1 is a flow chart illustrating a prior art method for fabricating a magnetic reader, and in particular for defining the stripe height of a read sensor of the magnetic reader.
- FIGS. 2-10 are cross-sectional views of a magnetic reader formed according to the method of FIG. 1 .
- FIG. 11 is a flow chart illustrating an exemplary method for fabricating a magnetic reader using a CMP process for sensor stripe height patterning.
- FIGS. 12-16 are cross-sectional views of a magnetic reader formed according to the method of FIG. 11 .
- FIG. 17 is a top view of a magnetic reader formed according to the method of FIG. 11 .
- FIG. 18 is a flow chart illustrating an exemplary method for fabricating a magnetic reader.
- FIGS. 19-24 are cross-sectional views of a magnetic reader formed according to the method of FIG. 18 .
- FIG. 25 is a top view of a magnetic reader formed according to the method of FIG. 18 .
- FIG. 1 is a flowchart illustrating a prior art process used for defining the stripe height of a read sensor of a magnetic reader.
- FIGS. 2-10 are cross-sectional views illustrating the layers of the magnetic reader during the stripe height fabrication process illustrated in FIG. 1 .
- step 102 of FIG. 1 sensor layers 206 are deposited on shield layer 202 (see FIG. 2 ).
- step 104 a first diamond like carbon (DLC) protective layer 302 is deposited on the sensor layers 206 (see FIG. 3 ).
- step 106 a masking layer 402 is deposited over the first DLC protective layer 302 .
- step 108 masking layer 402 is etched in a photolithographic process to form a mask structure 402 (see FIG. 4 ).
- FIG. 4 illustrates a sensor pattern mask structure 402 .
- mask structure 402 may also be formed in the field.
- the first DLC protective layer 302 is etched using a reactive ion etching (RIE) process. Any exposed areas of the first DLC protective layer 302 not protected by mask structure 402 are removed by exposure to the RIE process (see FIG. 5 ).
- sensor layers 206 are etched using an ion milling process to define read sensor 602 with desired dimensions as illustrated in FIG. 6 .
- an insulator layer 702 is deposited over read sensor 602 , as illustrated in FIG. 7 .
- a second DLC protective layer 802 is deposited over insulator layer 702 as a stop layer for a CMP lift-off process (see FIG. 8 ).
- a CMP lift-off process is performed down to the stop layer. The CMP lift-off process removes mask structure 402 and material deposited above mask structure 402 , such as overfill insulator material 702 . The resulting structure is illustrated in FIG. 9 .
- step 120 a second RIE process is used to remove first DLC protective layer 302 and second DLC protective layer 802 .
- the resulting structure is illustrated in FIG. 10 .
- the prior art process described in FIG. 1 typically encounters fencing or alumina bumps at edges of read sensor 602 fabricated by the stripe height definition process. This added topography may cause shield shorts and sensor shunts subsequent to the track width definition process because insulator layer 702 is not fabricated flush with read sensor 602 .
- FIGS. 11-25 and the following description depict specific exemplary embodiments of the invention to teach those skilled in the art how to make and use the invention. For the purpose of teaching inventive principles, some conventional aspects of the invention have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents.
- the typical fabrication process for magnetic readers involves depositing various layers of a magnetic reader on a wafer substrate. Two such layers are a first and second DLC protective layer, which act as stop layers during CMP lift-off. Such protective layers are typically removed before the fabrication process is completed.
- An exemplary embodiment of the invention eliminates the need for a second protective layer and uses only one protective layer.
- a patterned and conductive protective layer forms part of the sensor cap of the read sensor.
- the insulator layer is polished using a CMP process to achieve a flat reader gap.
- the exemplary embodiment eliminates the need for deposition of an entire layer in the fabrication process, which thereby also eliminates many of the negative byproducts of such deposition and removal, such as fencing and alumina bumps.
- FIG. 11 is a flow chart illustrating a method 1100 for fabricating magnetic readers in an exemplary embodiment of the invention. Method 1100 will be described in reference to magnetic reader 1200 in FIGS. 12-17 . The steps of the flow chart in FIG. 11 are not all inclusive and may include other steps not shown. Fabrication of magnetic readers is commonly performed at the wafer level, and those skilled in the art understand that wafer level fabrication is assumed even if the description and drawings refer to a single magnetic reader.
- step 1102 sensor layers 206 (see FIG. 12 ) for a magnetic reader 1200 are deposited on a shield layer 202 .
- the sensor layers may be deposited during a stripe height definition process defining the stripe height of a read sensor of magnetic reader 1200 .
- a conductive protective layer 1202 (see FIG. 12 ) is deposited on sensor layers 206 .
- Conductive protective layer 1202 acts as a stop layer during a later CMP process, and forms the sensor cap of magnetic reader 1200 .
- Conductive protective layer 1202 may be any suitable conductive material, such as Rhodium (Rh). Rh has a CMP material removal rate (2 Angstroms/min) that is comparable to DLC (2 Angstroms/min). The removal rate of Rh is significantly lower than other materials used in magnetic reader fabrication (e.g., Ru (60 A/min), Cr (70 A/min), Ta (1200 A/min) and Al 2 O 3 (3000 A/min)).
- a masking layer 402 is deposited on conductive protective layer 1202 .
- Masking layer 402 is a photo resistive layer used to define the stripe height or track width of a read sensor of magnetic reader 1200 .
- Masking layer 402 may be made of Duramide®, a registered trademark of Cambrex Bio Science Rockland, Inc.
- a mask structure 402 is formed from masking layer 402 .
- masking layer 402 is light exposed in a pattern to remove desired regions of masking layer 402 . If masking layer 402 is a positive photo resist, then masking layer 402 is light-exposed in regions to be removed. Otherwise, if masking layer 402 is a negative photo resist, then masking layer 402 is light-exposed in regions to be retained. The resulting structure of magnetic reader 1200 is illustrated in FIG. 12 .
- conductive protective layer 1202 is etched through mask structure 402 using an ion milling process to pattern sensor layers 206 and conductive protective layer 1202 .
- the ion milling process defines a read sensor 1302 of magnetic reader 1200 (see FIG. 13 ).
- the defined read sensor 1302 is produced by removing portions of sensor layers 206 through the ion milling process.
- the etching process may define the stripe height of read sensor 1302 .
- Read sensor 1302 has a field on side regions of read sensor 1302 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 13 .
- an insulator layer 1402 is deposited on read sensor 1302 (see FIG. 14 ). Insulator layer 1402 is deposited on side regions (i.e., in the field) of read sensor 1302 to a height above conductive protective layer 1202 (i.e., on read sensor 1302 ). The overfill portion of insulator layer 1402 above read sensor 1302 may then be removed during the CMP process.
- step 1114 a lift-off process is performed down to conductive protective layer 1202 to remove mask structure 402 on side regions of read sensor 1302 . Any material above mask structure 402 in the field of read sensor 1302 , such as an overfill portion of insulator layer 1402 is removed with mask structure 402 .
- the resulting structure of magnetic sensor 1200 is illustrated in FIG. 15 .
- a CMP process is performed to remove masking layer 402 (i.e., sensor pattern mask structure 402 ) above read sensor 1302 .
- the CMP process planarizes insulator layer 1402 with conductive protective layer 1202 . Overfill portions of insulator layer 1402 (see FIG. 15 ) at a height above conductive protective layer 1202 are polished and removed. Once the CMP process stops at conductive protective layer 1202 , insulator layer 1402 will be planarized, as exemplified in FIG. 16 . Insulator layer 1302 is thus fabricated flush with read sensor 1302 to achieve a flat reader gap. Conductive protective layer 1202 remains above read sensor 1302 and sensor layers 206 in the field area (i.e., on side regions of read sensor 1302 ).
- FIG. 17 illustrates a top view of magnetic reader 1200 .
- Read sensor 1302 is below protective layer 1202 in the center portion of magnetic reader 1200 .
- Sensor layers 206 are below conductive protective layer 1202 in the outer portion of magnetic reader 1200 .
- Sensor layers 206 may be removed during the subsequent fabrication process and the resulting gap may be filled with insulator material to fabricate magnetic reader 1200 with a flat reader gap. Additionally, a track width of read sensor 1302 may be defined to complete the fabrication of read sensor 1302 .
- FIG. 18 is a flow chart illustrating a method 1800 for fabricating magnetic readers in an exemplary embodiment of the invention. Method 1800 will be described in reference to magnetic reader 1200 in FIGS. 12-17 and 19 - 25 . The steps of the flow chart in FIG. 18 are not all-inclusive and may include other steps not shown.
- read sensor 1302 is etched to define a track width of read sensor 1302 .
- Defining a track width of read sensor 1302 may involve depositing a masking layer over magnetic reader 1200 (i.e., over conductive protective layer 1202 ) to form a mask structure, ion milling protective layer 1202 and read sensor 1302 to define the track width of read sensor 1302 , depositing an insulator layer 1904 and a hard bias layer 1902 , and then removing the mask structure.
- FIG. 19 illustrates magnetic reader 1200 after completion of the track width definition process.
- a bi-layer photo resistive structure 2002 is deposited on magnetic reader 1200 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 20 .
- an ion milling process is performed on read sensor 1200 around bi-layer photo resistive structure 2002 to remove sensor layers 206 and conductive protective layer 1202 in the field (i.e., on side regions) of read sensor 1302 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 21 .
- a refill insulator layer 2202 is deposited on magnetic reader 1200 .
- Refill insulator layer 2202 may be Alumina (Al 2 O 3 ), and may be deposited to a height above conductive protective layer 1202 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 22 .
- step 1810 a lift-off process is performed to remove bi-layer photo resistive structure 2002 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 23 .
- step 1812 a shield layer 2402 may then be deposited on magnetic reader 1200 .
- the resulting structure of magnetic reader 1200 is illustrated in FIG. 24 .
- FIG. 25 illustrates a top view of magnetic sensor 1200 fabricated by method 1800 .
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Abstract
Description
- 1. Field of the Invention
- The invention is related to the field of magnetic recording head fabrication, and in particular, to improved methods of fabricating a read sensor which involve using a chemical mechanical polishing (CMP) process with a patterned conductive CMP protective layer for sensor stripe height patterning.
- 2. Statement of the Problem
- Magnetic disk drive systems typically include a magnetic disk, a magnetic recording head having read and write elements, a suspension arm, and an actuator arm. As the magnetic disk is rotated, air adjacent to the disk surface moves with the disk. This allows the magnetic recording head (also referred to as a slider) to fly on an extremely thin cushion of air, generally referred to as an air bearing. When the magnetic recording head flies on the air bearing, the actuator arm swings the suspension arm to place the magnetic recording head over selected circular tracks on the rotating magnetic disk where signal fields are written to and read by the write and read elements, respectively. The write and read elements are connected to processing circuitry that operates according to a computer program to implement write and read functions.
- The magnetic recording head is typically produced using thin-film deposition and patterning techniques. The magnetic head reader fabrication involves two separate patterning processes. One process defines the stripe height of the read sensor, while another process defines the track width of the read sensor. In particular, the several material layers which make up a read sensor for a magnetic reader are typically formed by depositing full film sensor layers of the required materials on a wafer substrate, depositing and patterning a masking layer over the sensor layers to form a mask structure, etching the exposed portion of the sensor layers around the mask structure, and then removing the mask structure.
- The mask structure is removed using a CMP assisted lift-off process. CMP protective layers (also called CMP stop layers) are deposited between various layers of the fabricated structure to protect other layers, such as sensor layers and insulation during the CMP lift-off process. These protective layers are then removed using another etching process (e.g., reactive ion etching or ion milling).
- Problems are encountered in the prior art process because alumina bumps or fencing may occur at edges of sensor after the stripe height definition process. This added topography may cause shield shorts and sensor shunt subsequent to the track width definition process because the insulator layer is not fabricated flat with the read sensor. It is evident from the above discussion that improved solutions are needed for fabricating magnetic readers using new processes.
- The invention solves the above and other related problems with improved methods for fabricating a magnetic reader using a CMP process with a patterned CMP conductive protective layer for sensor stripe height patterning. After a sensor is patterned and an insulator layer is deposited, the CMP process is used to planarize the insulator layer. The CMP process stops at the CMP conductive protective layer. The CMP conductive protective layer may be left in place as sensor cap of a read sensor of the magnetic reader. The invention eliminates the alumina bumps typically encountered by prior art stripe height definition processes using DLC protective layers. The invention also allows for the elimination of a second protective layer (e.g., a DLC layer) used in prior art stripe height definition processes.
- A first exemplary embodiment comprises a method for fabricating magnetic readers. The method comprises defining a read sensor of a magnetic reader. The method further comprises depositing an insulator layer on the read sensor. The method further comprises performing a CMP process down to a conductive protective layer deposited while defining the read sensor to remove an overfill portion of the insulator layer above the conductive protective layer and to remove a sensor pattern mask structure above the conductive protective layer.
- A second exemplary embodiment of the invention comprises a method for fabricating magnetic readers. The method comprises defining a stripe height of a read sensor of a magnetic reader. The read sensor has a field on side regions of the read sensor. During the stripe height definition process a conductive protective layer is formed above a top portion of the read sensor to protect the read sensor. The method further comprises depositing an insulator layer on the read sensor. The insulator layer is deposited in the field of the read sensor to a height above the conductive protective layer. The method further comprises performing a CMP process down to the conductive protective layer. The CMP process removes an overfill portion of the insulator layer above the conductive protective layer, planarizes the insulator layer with the conductive protective layer and removes a sensor pattern mask structure above the conductive protective layer. The method further comprises defining a track width of the read sensor. The method further comprises depositing a bi-layer photo resistive structure on the magnetic reader. The method further comprises milling the magnetic reader to remove material on side regions of the bi-layer photo resistive structure. The method further comprises depositing insulator material on side regions of the bi-layer photo resistive structure. The method further comprises performing a lift-off process to remove the bi-layer photo resistive structure. As a result, the insulator layer is planarized and flush with the read sensor, eliminating fencing typically encountered at the edges of the insulator layer.
- A third exemplary embodiment is a method for fabricating magnetic readers. The method comprises depositing sensor layers. The method further comprises depositing a conductive protective layer on the sensor layers. The method further comprises depositing a masking layer on the conductive protective layer. The masking layer is etchable for definition of a mask structure. The method further comprises etching the conductive protective layer around the mask structure to remove a portion of the conductive protective layer. The method further comprises etching the sensor layers to define a stripe height of a read sensor of the magnetic reader. The method further comprises depositing an insulator layer on the read sensor. The method further comprises performing a CMP process down to the conductive protective layer.
- The invention may include other exemplary embodiments described below.
- The same reference number represents the same element or similar type of element on all drawings.
-
FIG. 1 is a flow chart illustrating a prior art method for fabricating a magnetic reader, and in particular for defining the stripe height of a read sensor of the magnetic reader. -
FIGS. 2-10 are cross-sectional views of a magnetic reader formed according to the method ofFIG. 1 . -
FIG. 11 is a flow chart illustrating an exemplary method for fabricating a magnetic reader using a CMP process for sensor stripe height patterning. -
FIGS. 12-16 are cross-sectional views of a magnetic reader formed according to the method ofFIG. 11 . -
FIG. 17 is a top view of a magnetic reader formed according to the method ofFIG. 11 . -
FIG. 18 is a flow chart illustrating an exemplary method for fabricating a magnetic reader. -
FIGS. 19-24 are cross-sectional views of a magnetic reader formed according to the method ofFIG. 18 . -
FIG. 25 is a top view of a magnetic reader formed according to the method ofFIG. 18 . -
FIG. 1 is a flowchart illustrating a prior art process used for defining the stripe height of a read sensor of a magnetic reader.FIGS. 2-10 are cross-sectional views illustrating the layers of the magnetic reader during the stripe height fabrication process illustrated inFIG. 1 . - In
step 102 ofFIG. 1 , sensor layers 206 are deposited on shield layer 202 (seeFIG. 2 ). Instep 104, a first diamond like carbon (DLC)protective layer 302 is deposited on the sensor layers 206 (seeFIG. 3 ). Instep 106, amasking layer 402 is deposited over the first DLCprotective layer 302. Instep 108, maskinglayer 402 is etched in a photolithographic process to form a mask structure 402 (seeFIG. 4 ).FIG. 4 illustrates a sensorpattern mask structure 402. Those of ordinary skill in the art will recognize thatmask structure 402 may also be formed in the field. - In
step 110, the first DLCprotective layer 302 is etched using a reactive ion etching (RIE) process. Any exposed areas of the first DLCprotective layer 302 not protected bymask structure 402 are removed by exposure to the RIE process (seeFIG. 5 ). Instep 112, sensor layers 206 are etched using an ion milling process to defineread sensor 602 with desired dimensions as illustrated inFIG. 6 . - In
step 114, aninsulator layer 702 is deposited over readsensor 602, as illustrated inFIG. 7 . Instep 116, a second DLCprotective layer 802 is deposited overinsulator layer 702 as a stop layer for a CMP lift-off process (seeFIG. 8 ). Instep 118, a CMP lift-off process is performed down to the stop layer. The CMP lift-off process removesmask structure 402 and material deposited abovemask structure 402, such asoverfill insulator material 702. The resulting structure is illustrated inFIG. 9 . - In
step 120, a second RIE process is used to remove first DLCprotective layer 302 and second DLCprotective layer 802. The resulting structure is illustrated inFIG. 10 . The prior art process described inFIG. 1 typically encounters fencing or alumina bumps at edges ofread sensor 602 fabricated by the stripe height definition process. This added topography may cause shield shorts and sensor shunts subsequent to the track width definition process becauseinsulator layer 702 is not fabricated flush withread sensor 602. -
FIGS. 11-25 and the following description depict specific exemplary embodiments of the invention to teach those skilled in the art how to make and use the invention. For the purpose of teaching inventive principles, some conventional aspects of the invention have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. - As described in
FIG. 1 , the typical fabrication process for magnetic readers involves depositing various layers of a magnetic reader on a wafer substrate. Two such layers are a first and second DLC protective layer, which act as stop layers during CMP lift-off. Such protective layers are typically removed before the fabrication process is completed. An exemplary embodiment of the invention eliminates the need for a second protective layer and uses only one protective layer. A patterned and conductive protective layer forms part of the sensor cap of the read sensor. The insulator layer is polished using a CMP process to achieve a flat reader gap. Thus, the exemplary embodiment eliminates the need for deposition of an entire layer in the fabrication process, which thereby also eliminates many of the negative byproducts of such deposition and removal, such as fencing and alumina bumps. -
FIG. 11 is a flow chart illustrating amethod 1100 for fabricating magnetic readers in an exemplary embodiment of the invention.Method 1100 will be described in reference tomagnetic reader 1200 inFIGS. 12-17 . The steps of the flow chart inFIG. 11 are not all inclusive and may include other steps not shown. Fabrication of magnetic readers is commonly performed at the wafer level, and those skilled in the art understand that wafer level fabrication is assumed even if the description and drawings refer to a single magnetic reader. - In
step 1102, sensor layers 206 (seeFIG. 12 ) for amagnetic reader 1200 are deposited on ashield layer 202. The sensor layers may be deposited during a stripe height definition process defining the stripe height of a read sensor ofmagnetic reader 1200. - In
step 1104, a conductive protective layer 1202 (seeFIG. 12 ) is deposited on sensor layers 206. Conductiveprotective layer 1202 acts as a stop layer during a later CMP process, and forms the sensor cap ofmagnetic reader 1200. Conductiveprotective layer 1202 may be any suitable conductive material, such as Rhodium (Rh). Rh has a CMP material removal rate (2 Angstroms/min) that is comparable to DLC (2 Angstroms/min). The removal rate of Rh is significantly lower than other materials used in magnetic reader fabrication (e.g., Ru (60 A/min), Cr (70 A/min), Ta (1200 A/min) and Al2O3 (3000 A/min)). - In
step 1106, amasking layer 402 is deposited on conductiveprotective layer 1202. Maskinglayer 402 is a photo resistive layer used to define the stripe height or track width of a read sensor ofmagnetic reader 1200. Maskinglayer 402 may be made of Duramide®, a registered trademark of Cambrex Bio Science Rockland, Inc. - In
step 1108, amask structure 402 is formed from maskinglayer 402. To formmask structure 402, maskinglayer 402 is light exposed in a pattern to remove desired regions of maskinglayer 402. If maskinglayer 402 is a positive photo resist, then maskinglayer 402 is light-exposed in regions to be removed. Otherwise, if maskinglayer 402 is a negative photo resist, then maskinglayer 402 is light-exposed in regions to be retained. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 12 . - In
step 1110, conductiveprotective layer 1202 is etched throughmask structure 402 using an ion milling process to pattern sensor layers 206 and conductiveprotective layer 1202. The ion milling process defines aread sensor 1302 of magnetic reader 1200 (seeFIG. 13 ). The definedread sensor 1302 is produced by removing portions ofsensor layers 206 through the ion milling process. The etching process may define the stripe height ofread sensor 1302. Readsensor 1302 has a field on side regions ofread sensor 1302. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 13 . - In
step 1112, aninsulator layer 1402 is deposited on read sensor 1302 (seeFIG. 14 ).Insulator layer 1402 is deposited on side regions (i.e., in the field) ofread sensor 1302 to a height above conductive protective layer 1202 (i.e., on read sensor 1302). The overfill portion ofinsulator layer 1402 aboveread sensor 1302 may then be removed during the CMP process. - In
step 1114, a lift-off process is performed down to conductiveprotective layer 1202 to removemask structure 402 on side regions ofread sensor 1302. Any material abovemask structure 402 in the field ofread sensor 1302, such as an overfill portion ofinsulator layer 1402 is removed withmask structure 402. The resulting structure ofmagnetic sensor 1200 is illustrated inFIG. 15 . - In
step 1116, a CMP process is performed to remove masking layer 402 (i.e., sensor pattern mask structure 402) aboveread sensor 1302. The CMP process planarizesinsulator layer 1402 with conductiveprotective layer 1202. Overfill portions of insulator layer 1402 (seeFIG. 15 ) at a height above conductiveprotective layer 1202 are polished and removed. Once the CMP process stops at conductiveprotective layer 1202,insulator layer 1402 will be planarized, as exemplified inFIG. 16 .Insulator layer 1302 is thus fabricated flush withread sensor 1302 to achieve a flat reader gap. Conductiveprotective layer 1202 remains aboveread sensor 1302 andsensor layers 206 in the field area (i.e., on side regions of read sensor 1302). -
FIG. 17 illustrates a top view ofmagnetic reader 1200. Readsensor 1302 is belowprotective layer 1202 in the center portion ofmagnetic reader 1200. Sensor layers 206 are below conductiveprotective layer 1202 in the outer portion ofmagnetic reader 1200. Sensor layers 206 may be removed during the subsequent fabrication process and the resulting gap may be filled with insulator material to fabricatemagnetic reader 1200 with a flat reader gap. Additionally, a track width ofread sensor 1302 may be defined to complete the fabrication ofread sensor 1302. -
FIG. 18 is a flow chart illustrating amethod 1800 for fabricating magnetic readers in an exemplary embodiment of the invention.Method 1800 will be described in reference tomagnetic reader 1200 inFIGS. 12-17 and 19-25. The steps of the flow chart inFIG. 18 are not all-inclusive and may include other steps not shown. - In
step 1802, readsensor 1302 is etched to define a track width ofread sensor 1302. Defining a track width ofread sensor 1302 may involve depositing a masking layer over magnetic reader 1200 (i.e., over conductive protective layer 1202) to form a mask structure, ion millingprotective layer 1202 and readsensor 1302 to define the track width ofread sensor 1302, depositing aninsulator layer 1904 and ahard bias layer 1902, and then removing the mask structure.FIG. 19 illustratesmagnetic reader 1200 after completion of the track width definition process. - In
step 1804, a bi-layer photoresistive structure 2002 is deposited onmagnetic reader 1200. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 20 . Instep 1806, an ion milling process is performed onread sensor 1200 around bi-layer photoresistive structure 2002 to removesensor layers 206 and conductiveprotective layer 1202 in the field (i.e., on side regions) ofread sensor 1302. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 21 . - In
step 1808, arefill insulator layer 2202 is deposited onmagnetic reader 1200.Refill insulator layer 2202 may be Alumina (Al2O3), and may be deposited to a height above conductiveprotective layer 1202. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 22 . - In
step 1810, a lift-off process is performed to remove bi-layer photoresistive structure 2002. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 23 . Instep 1812, ashield layer 2402 may then be deposited onmagnetic reader 1200. The resulting structure ofmagnetic reader 1200 is illustrated inFIG. 24 .FIG. 25 illustrates a top view ofmagnetic sensor 1200 fabricated bymethod 1800. - Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents therein.
Claims (20)
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